The human body is full of mysteries. Although medical science has progressed greatly in knowing a lot about different organs and parts of the body, what we know is just a drop in the ocean. Today we are going to learn some interesting facts about one of the most important parts of the body- the stomach. The stomach is the organ that receives food through the esophagus. It acts as the primary repository of what we eat. It is round, hollow, muscular, and expendable. It is internally located in the body and is bean-shaped. It is a sac-like structure protected by the lower ribs.

Our stomach secretes gastric juices that help the digestion of food and stores the molecules of food. The general approximate capacity of the human stomach is a quarter gallon, which means it can hold about half a pound of food at a time. In this chapter, we will discover some cool facts about the human stomach.

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Amazing Facts About the Stomach

Fact 1- Capacity of the Stomach

At rest, a stomach can hold about half a pound of the food and 7 ounces of stomach acid and bile at a time. Its average capacity is 32 ounces, which is amazingly good. One meal on an average is digested in 4 to 6 hours, so the capacity of the stomach is important as it acts as the repository of food.

Fact 2- A Person Can Survive Without a Stomach

It is possible to survive even without the stomach with an altered diet and small and frequent meals. Total gastrectomy is the surgical removal of the stomach in which the esophagus is directly attached to the small intestine.

Fact 3- Stomach Holds Concentrated Acid Without Being Corroded or Damaged by it

The stomach has a lining that keeps regenerating on regular intervals to keep the stomach acid intact and the pH maintained. The lining of the stomach also produces some goblet mucus cells to protect itself from the corrosive nature of the hydrochloric acid.

Fact 4- Absorption of Some Vitamins from Food

The stomach is also found to be responsible for absorbing some important vitamins like Vitamin b12 from the food we eat. Hydrochloric acid in the stomach and pepsin enzyme break the locked Vitamin B12 out of its protein so it can be absorbed into the bloodstream.

Fact 5- Generation of Hormones

The epithelial cells lining the stomach play a vital role in the production of some hormones. These hormones are related to stimulating appetite, secreting necessary enzymes for digestion and gastric acid, and some hormones regulate the contraction of the gallbladder. These hormones directly enter the bloodstream from the stomach and affect the function of other parts of the digestive system, including the liver and pancreas, and even your brain.

Fact 6- As the First Line of Defense

The stomach acts as the first line of defense in the immune system in the body. The stomach acid not only digests food but sterilizes everything that we eat. Thereby killing many potential bacteria and food toxins. The gastrointestinal tract also has patches of lymphoid defense cells that are sent out when something makes it through the stomach, such as a virus or bacteria that have the potency to cause infection.

Fact 7- Stomach of Other Animals

The stomachs of a few animals like cows, giraffes, cattle, deer are four-chambered. Such morphology of the stomach helps them digest the plant-based food, which is the hardest diet compared to other diets.

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Fact 8- Animals with No Stomach

There are certain animals like carp, lungfishes, seahorses, and platypuses who do not have a stomach. Their esophagus is directly connected to the intestine, which is where the food goes right after ingestion.

Fact 9- Protective Layer of the Stomach

The mucous layer in the stomach is produced every two weeks to protect the stomach and other neighboring organs from being corroded or damaged by the hydrochloric acid.

Fact 10- Hydrochloric Acid in the Stomach

The hydrochloric acid in the stomach is so concentrated and corrosive that it can even dissolve metals. But the stomach itself remains protected by it with the help of the mucous layer.

Fact 11- Easily Digestible Foods

Sugary foods are easily digestible and foods with high fat and protein take more time to digest. A normal meal is digested in five to seven hours whereas, high fiber and protein-containing food are digested a little more over this duration.

Fact 12- Size of the Stomach

The average size of the stomach is about 12 inches long and 6 inches wide and is almost the same for everyone. The size of the stomach does not vary with the weight of the individual. Therefore, thin people and obese people, both have the same stomach sizes.

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FAQs on Essential Facts About the Stomach

1. What are the four main anatomical parts of the stomach?

The human stomach is anatomically divided into four main regions, each with a specific role in digestion:

Cardia: The top part of the stomach where the esophagus connects. It contains the cardiac sphincter, which prevents stomach contents from flowing back up.
Fundus: The rounded upper part of the stomach next to the cardia. It often fills with gas that is released during digestion.
Body (Corpus): The largest central section of the stomach, where most of the mixing and digestion occurs.
Pylorus: The lower, funnel-shaped part that connects the stomach to the small intestine. It controls the release of partially digested food (chyme) through the pyloric sphincter.

2. What are the primary functions of the stomach in the digestive system?

The stomach performs several crucial functions to process food before it enters the small intestine. Its primary roles include:

Temporary Storage: It acts as a reservoir, holding food after a meal, and releasing it slowly into the small intestine.
Mechanical Digestion: The strong muscular walls of the stomach contract and churn, physically breaking down food and mixing it with digestive juices to form a semi-liquid substance called chyme.
Chemical Digestion: It secretes hydrochloric acid (HCl) and enzymes like pepsin to begin the chemical breakdown of proteins.
Disinfection: The highly acidic environment kills most harmful bacteria and pathogens present in the food.

3. Why doesn't the stomach digest itself, despite its powerful acid?

The stomach has a sophisticated self-protection system to prevent its own tissues from being damaged by hydrochloric acid and digestive enzymes. This is achieved through three key mechanisms:

Thick Mucus Layer: The stomach's inner lining is coated with a thick, alkaline layer of mucus that acts as a physical barrier between the stomach wall and the acidic contents.
Bicarbonate Secretion: The cells of the stomach lining secrete bicarbonate, an alkaline substance that neutralises the acid right at the surface of the wall.
Rapid Cell Regeneration: The epithelial cells lining the stomach have a very short lifespan and are replaced every few days, ensuring any damaged cells are quickly shed and replaced.

4. What is the difference between mechanical and chemical digestion that occurs in the stomach?

Both mechanical and chemical digestion are essential processes in the stomach, but they work differently. Mechanical digestion refers to the physical breakdown of food. In the stomach, this is achieved by the churning and mixing actions of its muscular walls (a process called maceration), which turns large food particles into a liquid pulp called chyme. Chemical digestion, on the other hand, involves breaking down food using chemicals. In the stomach, this is primarily the work of hydrochloric acid and the enzyme pepsin, which specifically target and break down large protein molecules into smaller peptides.

5. What is the specific role of hydrochloric acid (HCl) in the stomach?

Hydrochloric acid (HCl) creates a highly acidic environment in the stomach (pH 1.5-3.5) and serves several vital functions:

Activation of Pepsin: It converts the inactive enzyme pepsinogen into its active form, pepsin, which is necessary for protein digestion.
Killing Pathogens: Its strong acidity effectively kills most bacteria, viruses, and other microorganisms ingested with food, preventing foodborne illnesses.
Denaturing Proteins: It helps to unravel the complex structures of proteins, making them more accessible for enzymatic digestion by pepsin.

6. How long does food typically stay in the stomach?

The time food spends in the stomach can vary significantly, generally ranging from 2 to 4 hours. However, this duration depends on the composition of the meal. Carbohydrate-rich foods, like fruits and starches, are digested relatively quickly. Proteins take longer, and fatty or oily foods spend the most time in the stomach, as fats slow down the emptying process.

7. What are the four layers that make up the stomach wall?

The wall of the stomach is composed of four distinct layers, arranged from the inside out:

Mucosa: The innermost layer that secretes mucus, acid, and digestive enzymes. It is folded into ridges called rugae, which allow the stomach to expand.
Submucosa: A layer of connective tissue that contains blood vessels, lymphatic vessels, and nerves. It supports the mucosa.
Muscularis Externa: This is a powerful muscle layer, uniquely composed of three sub-layers (oblique, circular, and longitudinal), which contract to churn and mix food.
Serosa: The outermost protective layer, which is a smooth membrane that reduces friction against other abdominal organs.

8. Can a person live without a stomach, and how does the digestive process change?

Yes, a person can survive without a stomach. The surgical procedure to remove the stomach is called a total gastrectomy. In this procedure, the surgeon connects the esophagus directly to the small intestine. While life is possible, the digestive process is significantly altered. The person must eat much smaller, more frequent meals because there is no stomach to store food. Additionally, since the stomach produces intrinsic factor (essential for vitamin B12 absorption), patients often require lifelong vitamin B12 injections to prevent anaemia.